Carrier aggregation is a feature of LTE-Advanced (Long Term Evolution-Advanced or LTE-A) as part of Release 10 of the LTE specification by the 3rd Generation Partnership Project (3GPP) for increasing data rates by aggregating multiple carriers together to increase total bandwidth. The multiple carriers, referred to as component carriers, may occupy contiguous or non-contiguous bandwidths. A component carrier is also sometimes referred to as a serving cell. For time-division duplex (TDD), a serving cell is a single carrier frequency where, for uplink and downlink transmissions between a user equipment (UE) and an enhanced Node-B (eNB) occur in different subframes. For frequency division duplex (FDD), a serving cell includes two different carrier frequencies or downlink and uplink transmissions. Each UE has a single serving cell, referred to as the primary cell (PCell), that provides all the necessary control functions used to communicate with the eNB. All other serving cells are referred to as secondary cells (SCells). Improved techniques for maintaining timing and frequency synchronization are needed for certain types of SCells.